1. Field of the Invention
In one aspect, the invention relates to substituted alkoxy benzenes. In another aspect, the invention relates to polyepoxide resin compositions. In a preferred embodiment, the invention relates specifically to polyepoxide resin compositions and associated methods useful for consolidating particulate material, e.g., sand, into hard permeable masses in subterranean formations.
2. Description of the Prior Art
Polyepoxide resin compositions and associated methods useful for consolidating particulate material into hard permeable masses have been developed and used heretofore. Such compositions and methods are commonly used in the oil and gas industry, for example, to form hard permeable masses in subterranean formations containing loose or incompetent sands. The hard permeable masses reduce or prevent migration of the loose or incompetent sands into the well bores with hydrocarbons produced from the formations. Such compositions and methods are also commonly used in the oil and gas industry in well stimulation procedures such as formation fracturing wherein hard permeable masses of particulate material are used to keep fractures open and/or prevent loose proppants from flowing back into the well bores.
One technique which has heretofore been utilized successfully for forming a consolidated, permeable particulate mass in a producing formation involves coating the formation sand adjacent the well bore with a hardenable polyepoxide resin and then causing the resin to harden. An alternate technique used heretofore involves coating sand or other particulate material with a hardenable polyepoxide resin on the surface, suspending the coated material in a gelled aqueous carrier liquid and pumping the suspension by way of the well bore into the formation whereby the resin coated material is deposited therein. The component streams can be batch mixed or continuously mixed "on-the-fly". The resin on the deposited material is caused or permitted to harden whereby a solid, permeable particulate mass is formed.
Methods of forming and suspending consolidatible polyepoxide resin coated particulate material in a gelled aqueous carrier liquid and transporting the coated particulate material by way of the gelled aqueous carrier liquid to a zone in which it is consolidated on a substantially instantaneous and continuous basis are described in U.S. Pat. No. 4,829,100 to Murphey et al. issued May 9, 1989. In accordance with such methods, substantially continuous streams of a gelled aqueous carrier liquid, uncoated particulate material, a polyepoxide resin composition which will subsequently harden and a surface active agent are admixed whereby the particulate material is continuously coated with the resin composition and suspended in the gelled aqueous carrier liquid. The resin has a sufficiently long curing or working time to enable continuous deposition of the suspension of gelled aqueous carrier liquid and coated particulate material in a desired location of a subterranean zone. Subsequent hardening of the resin in the zone produces the desired hard permeable mass of consolidated particulate material.
A problem often encountered with compositions and methods for consolidating particulate material into hard permeable masses is insufficient coating of the particulate material with the polyepoxide resin. It is difficult to coat particulate material with a polyepoxide resin in an aqueous environment, particularly an aqueous environment associated with high temperature and other adverse conditions. For example, when exposed to a high temperature (e.g., above about 160.degree. F.), the resin tends to disperse as finer droplets in the aqueous phase as opposed to sticking to the surfaces of the particulate material. The time for condensation of the droplets is increased. The problem is even further magnified when the aqueous phase of the system is viscosified with guar gum and/or other viscosifiers. Insufficient resin coating of the particulate material causes the consolidated mass to have a relatively low compressive strength.
As a solution, various surface active agents have been used to strongly oil wet the particulate material in order to increase the ability of the resin to wet the material; however, under high temperature and other adverse conditions, insufficient resin wetting still occurs. It is known that certain compounds used for accelerating or catalyzing the epoxide resin curing reaction also improve the ability of the resin to wet particulate material. For example, U.S. Pat. No. 4,291,766 to Davies et al. discloses the use of dimethylaminomethylene phenol to improve resin wetting of particulate material. It is disclosed that the dimethylaminomethylene phenol also accelerates the epoxide resin curing reaction. Unfortunately, the increased rate of curing can cause premature hardening of the resin in high temperature environments where accelerated curing occurs naturally. Premature hardening of the resin can prevent the coated particles from being placed in the formation where desired and cause serious damage to the formation, well bore and/or pumping equipment. The increased rate of curing can also cause the resin to cure before it even has a chance to coat the particulate material. Although curing retarders can be included to slow the reaction down, they can be costly and problematic. Because the retarding reaction is pH, temperature and concentration dependent, it can be difficult to select the right type and amount of retarders to use.